Natural stones, such as granite and marble, can have beautiful patterns on the surface thereof and thus have been used as building decoration material. Recently, the demand for natural stones for use in applications such as flooring, wall panels, sinks and the like, has significantly increased. However, this demand cannot be met only with high cost natural stones. Accordingly, various artificial marbles are also being developed and used.
Natural stones can be converted into common artificial stone by mixing the natural stone with various materials, such as inorganic fillers, coloring agents, hardening agents, and acrylic or unsaturated polyester base resins. Natural stones reinforced by resin can be subject to a vacuum-compression molding process, in which a composition including natural inorganic (silica) minerals and binder resins are mixed in order to form an artificial marble that can exhibit the texture of a natural stone. This type of product is referred generally in the art as engineered stone.
Resin reinforced natural stones can be prepared to display various colors and textures similar to that of the natural stones, resin, or color of the pigment. Since the main component of resin reinforced natural stone is a natural mineral, it can exhibit excellent natural textures, generally better than that exhibited by a common artificial stone. Accordingly, the demand for the same has recently increased.
A resin reinforced natural stone can be manufactured in single color tone or in multi-color tones by adding different pigments, or can be manufactured to have natural stone textures by using stone chips.
Current resin reinforced natural stones, however, do not typically exhibit properties sufficient to meet the desires of customers who require different textures.
To improve the function and performance of artificial marbles, a luminous function in the artificial marble can be provided using light emitting materials, such as UV radiation light emitting materials. This method can express the stone textures either by coating luminescent dyes on the surface of the artificial marbles or by using luminescent chips. However, when luminescent dyes are coated on the marble, their effect does not last long. The property of uniform luminescence cannot be obtained by using luminescent light emitting chips.
Also, the luminescent function of existing luminescent artificial marbles is not sufficient enough to be suitable for various applications. That is, from the point of view of its luminescent performance, existing artificial marbles have a drawback of not having a clear luminescence for around 15 minutes, which may be required in accordance with evacuation requirements for initial brightness, i.e. during a power failure. In addition, the time required to maintain the luminescence of the artificial marble up to 3 mcd/m2 as a lower limit to recognize the shape of object after irradiation with a light source is typically just one hour.
In addition, in existing luminescent artificial marbles, an excessive amount of luminescent pigment is typically used in order to achieve a sufficient luminescence performance. However, luminescent pigments are costly. Therefore, using an excessive amount of luminescent pigment increases the manufacturing cost, which would ultimately hinder commercialization. Therefore, there is a need to achieve sufficient luminescence property while keeping the amount of luminescent pigment used to a minimum.